The research undertaken in this project aims at further investigating the hypothesis of left hemisphere dysfunction and left hemisphere overactivation in schizophrenia, by using regional cerebral blood flow as a measure of hemispheric activation and using additional standardized measures of hemispheric competence. In addition, the work has been extended to the examination of brain lateralization in the affective psychoses. Our finding so far, based on lateral eye movements, as an index of hemispheric activation, and on cognitive tasks suggest that psychotically depressed patients overactivate their right hemisphere and do not manifest left hemispheric dysfunction. We are now in the process of gathering more data using the tachistoscopic technique. Regional cerebral blood flow is also employed to study the affect on ECT on blood flow and lateralization of cognitive functions. Another aspect of the work consists of the investigation of lateralization and expression of emotions. Recent data with normals, anectodal psychiatric observations, as well as neurological case studies strongly suggest hemispheric involvement in the expression of emotions. We are engaged, now, in data collection of psychiatric patients and controls. Finally, initial steps have been taken in the preparation for the longitudinal study on the etiology of laterality involvement in psychopathology. Files of participants in the National Collaborative Perinatal Projects were examined and a perinatal stress scale constructed. We are now examining the relationships among birth stress, laterality and psychopathology.